Diamidoformyl diphenylamin and process of making same.



UNITED STAT S- BATENT OFFICE.

OTTO soHsT, OF'HOOHST-ONQTHEMAIN, GERMANY, ASSIGNOR TO FARBWERKE, VORM. MEISTER, uc us & RUNING, OF ooHsT- ON-THE-MAIN, GERMANY, A oonr fonAT on on GERMANY.

DIAMIDOFORMYL DIPfiENYLAMlN AND PROCESS F MAKING SAME.-

Specification of Letters Patent.

Patented Nov. 28, 1905.

ApplicatiOll filed February 4. 1903. Serial No. 141,832. (Specimens)- citizen of the Empire of Germany, residing at -H6chst-on-the-Main, Germany, have invented certain new and useful Improvements in Para-Para1-Diamidoacidyldiphenylamin and its Transformation into Diamidophenylamin, of which the following is a specification.

Para-para1-diamidodiphenylamin has hitherto been obtained by reducing indamin; but as this process is inconvenient and the yield is not good a simpler and cheaper method for obtaining this technically-valuable base'has been sought.

The para-para1-dinitrodiphenylamin (Zeitsc/zm'ft f. ange'w. Ohemt'e, 1899, 1,051, and Berta/Lie, XVI, 2,576) readily obtainable by the nitration of acidy-l derivatives of diphenylalnin and subsequent hydrolysis'appears not to be suitable as parent material, for hitherto its reduction was only possible by use of the expensive stannous chlorid or zinc-dust and glacial acetic acid. (See above references.)

Nothing has been known hitherto about reducing the para-paraldinitrodiphenylamin with the comparatively cheap reducing agent, iron. Experiments have shown that it is possible to reduce the dinitro compound with iron; but the product cannot be separated in a pure state from the iron and in a rational manner, giving a good. yield.

By operating, for instance, in the manner already described in Bem'ohte, XXVIII, 2, 969, for ortho-para-dinitrodiphenylamin the yield of pure base is very moderate, and as the parap'arardiamidodiphenylamin is less soluble than the ortho-para-compound a large pro: portion of water is requisite to isolate the base from the reduced mass, and for this reason alone this mode of working is technically in applicable.

I have found that by using iron the reduction occurs more smoothly if for ,dinitrodi-.

phenylamin the acidyl-dinitrodiphenylamin is used; but by this modification the process does not become available for industrial purposes, for it is just as difficuit to isolate the.

ric or, better still, sulfuric acid without any decomposition or formation of color, as is the case, for instance, when operating with parapara1- or ortho-paradinitrodiphenylamim 'The acidyl-paraparal-diamidodiphenylamin, hitherto unknown, is readily obtained with a good yield by this process.

It is easily hydrolyzed. When heated with a an excess of sulfuric acid, it is transformed into para para1 diamidodipheny lamin. For

sulfate of para-paral-diamidodiphenylamin crystallizes when the solution is cold.

The dinitroacidyl compounds used as parent material namely, para-paral-dinitroformyldiphenylamin and para-parai-dinitroacetyldiphenylamin-may be obtained by di-nitrating the formyldiphenylarnin produced by the action of formic acidon diphenylmin (Berta/life, VIII, 1,195) or the acetyldiphenylamin in a sulfuric-acid solution containing a mixture of nitric and sulfuric acid (Ber. XIV, 2,366) in a similar manner as described in the Zeitschmlfif f. (mgew. Uhemz'e, 1899, p.1,051. The nitrated mixture is then poured into ice-water and the precipitate of feeble-yellow color is filtered, washed, and dried.

According to the above observations the reduction and hydrolysis may be carried out, for instance, as follows: Fourteen kilograms of finely-ground dinitroformyldiphenylamin, mixed With water, are slowly introduced into a mixture of thirty kilograms of iron-filings, two hundred and fifty liters of water,and about one -half kilogram of sulfuric acid of 66 Baum, specific gravity, heated to 60 to 90 centigrade. The whole is stirred at this temperature (about five hours) until the precipitate suspended in the reduced mass no longer appears brown. but black. The mass when cooled to 40 to 50 centigrade is then directly treated with 20-40 kilograms of sulfuric acid of fifty per cent. strength until an acid reaction sets in and hydrogen begins tov be evolved. It is then filtered, and when cold the base is separated from the filtrate by adding sodium acetate. The diamidoformyldiphenylamin is thus obtained as small slightlycolored crystals having the formula To obtain the para-paral-diamidodiphenylamin, the filtrate, which is obtained by acidifying the reduced mass with sulfuric acid, may be treated with about ten kilograms of sulfuric acid of 66 Baum, specific gravity, and then boiled. When cold, the difficultly-soluble sulfate of para-paral-diamidodiphenylamin then separates, forming a magma, while small proportions of isomeric bases remain in suspension.

If fordinitroformyldiphenylamin dinitroacetyldiphenylamin is used, the same products may be obtained. The hydrolysis, however, is somewhat slower.

The para-parm-diamidoformyl- (acetyl) -diphenylamin is to serve for the manufacture of dyestuffs and diamidodiphenylamin.

Having now described my invention, whatI claim is- 1. The process of making diamidoformyldiphenylamin, which consists in reducing dinitroformyldiphenylamin with iron in the presence of little acid, separating the base from the excess of iron by means of the easily-soluble sulfate and then isolating it with sodium acetate.

2. The process of making diamidodiphenylamin, which consists in reducing dinitroformyldiphenylamin with iron and then decomposing the diamidoformyldiphenylamin by heating it with acids.

3. As a new article of manufacture, the

para-para1 diamidoformyldiphenylamin having the formula HCO- OTTO SOHST.

Witnesses ALFRED BRISBOIS, BERNHARD LEYDECKER. 

